Process of burning bricks.



F. B. LAMBERT.

PROCESS oF BURNING BRICKS.

APPLICATION FILED MAR. 20. 1915.

Patented Sept. 4, N17.

3 SHEETS-SHEET l.

PVM/26556@ F. B. LAMBERT.

PROCESS 0F BURNING BRICKS.

APPucATloN man MAR.20.1915.

3 SHEETS-SHEET 2.

.2391, E. @9 Patented Sept. 4, 1917.

[M/M5565 ffwm Op W Wwe/ landje/wi F. B. LAMBERT.

PROCESS 0F BURNING BHICKS.

APPLlcAnoN FILED MAR. 2o. 1915.

Patented Set. 4, i917.

3 SHEETS-SHEET 3.

tof/2,696

rn sraarns FRANK B. LAMBERT, 0F CHICAGO, ILLINOIS, ASSIGNOR T0 LAMBERT PROCESS COM- '.PANY,l OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PROCESS 0F BURNING BRICKS.

Specification of Letters Patent.

ratentea sept. a', iai a.

Application led March 20, 1915. Serial No. 15,910. l

To all 'whom t may concern:

Be it known that I, FRANK B. LAMBERT, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Processes of Burning Bricks, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

The invention herein described comprisesan improved process of burning bricks. In my co-pending application Serial No. 681,- 720 I have set out a process for burning bricks. the present invention being an improvement on or refinement of the process set out in said application.

The invention disclosed in that application is the result of discoveries which I'have made in experimenting witha specific type of clay,l namely, the hardpan of the Chicago district. In that application I have made broad claims to the process. V

The present invention is the result of discoveries made by me in applying the broad idea of the prior invention to .other types of clay which required a definite manner ofapplication of the broad invention to arrive at a successful result. This application sets out and claims the definite orspecific manner of treatment which must be followed to insure success Iin burning.

The present invention enables me to decrease the time of burning a kiln very materially. It also enables me to carry on the process under proper control and it insures a product of high grade and uniform quality.

I have discovered that in burning bricks in accordance with the general method set out in my above-named application, the maintenance of a pressure balance which I shall hereafter fullydescribe, and the generation and holding of a blanket of steam, which will also be described fully, to maintain the pressure balance between the inside and lthe outside of the kiln, allows me to carry out the process with much greater certainty, under perfect control, and at greatly increased speed of operation.

With the aid of the accompanying drawings, which forni a part ofv this specification, I shall describe the specific manner in which my invention may be practised,l although it brick-widths in height.

' trating this stage of burning.

Fig. 5 is a view similar to Fig. 3, illustratingthe final step of burning when the blowing is about to be discontinued.

Fig. 6 is a view similar to Fig. 2 illustrating the stage of burning shown in Fig. 5.

The kiln shown in the drawings diagrammatically is a so-called temporary clamp kiln. In building the same, a layer of previously-burned bricks 1 is laid iiat on the ground to receive the dried bricks which are set above. The dried bricks may be set either by machine, or by hand, as may be found convenient, and no special arrangement of the bricks is found to be necessary,

tov

although it is preferable that the same be i set edgewise, in order lto provide suitable space between the bricks for the draft for the fire.

The first part of setting the bricks in the kiln consists in placing the bricks inv such position as to form the arches. These arches are placed about tive or six brick-lengths apart and are usually about six or seven The bricks are. usually piled in a kiln to a height of about 48 brick-widths, though it is understood that they may be stacked up to any conradiation due to exposure to the colder atmosphere. The thickness of the wall of double coal bricks is about the length of a single brick. These double coal bricks are made by mixing anthracite coal dust or heat within the kiln. It is well known that4 i heat of its own e'nergy travels only from a bodyl of high temperature to 4one of lower temperature, and, inasmuch as the wall of v burning double coal bricks is slightly hotter than 'the bricks inside, practically no heat from the inner bricks escapes to the outside,

and the process is carried out evenly through the entire kiln. Outside of the layer of double coal bricks 2 is placed a layer or wall iof previously-burned bricks 3, which is thicker for its lower half than for the upper half. The lower half is about a brick length in thickness, while the upper half is about a brick width in thickness. The bricks in this wall areI closely piledtogether and after the same is finished'the outer faces of the side vand end walls are plastered over, with a daubing of clay or loam, so as to close olf the outer air by pluggin up all the cracks andcrevices. A layer o previously-burned bricks may be placed on top of the kiln, but the. same are not daubed and th.n gases and water smoke from the kiln are free to escape between the fissures and the openings of the upper layer of bricks. The outer wall 3 of burned bricks is b uilt-Vr across the upper end of the arches, as indicated in the gures, and extensions 5 of the wall 3 are built around the openings to form what are called dog houses. A peephole 10 formed in the outer wall 3 allows the attendants to observe the action inside of the arch. The

side walls of the kiln may be braced against the posts or side of the shed within which the kiln is constructed. The end wall may be similarly braced, or may be'braced by props or struts, Aas is well known in the art.

On top of the kiln, at regular intervals, are placed a pile or vbrickbats, or a single brick 12, which just touches an irony rod 11,

which serves as a gage point for determining the settle of the kiln. The rod 11 may be secured in any suitable manner to the shed i within which the kiln is constructed.

After the kilnis properly set up the burn; ers 13 are put in place at each of the dog houses. This burner may be of any cony venient type, but I prefer to employ a burner of the general type shown ,in my prior application,- Serial No. 681,720. The burner is adapted to employ liquid fuel, which is furnished from a pipe 14 through a valve 15 and a exible tube 16 to the casing of the burner itself. Steam for atomizlng the liquid fuel and for driving the same into the kiln'is supplied by the pipe 17, which is is placed in the arch adjacent each dog house, so that the flamel from the burner 13 will impinge thereagainst.- The purpose of this brick is to Aform a sort of baflie in order to cause the flame to spread at this oint and to heat the adjacent unburned bric s and to start the double coal bricks burning slightly in advance of the main body of the bricks, as it is desirable that these bricks be burned slightly faster than the main body of the bricks. As soon as the bricks'adjacentv the dog house are brought to the desired temperature, the baiiie brick 20.is removed and the iame from'the burner 13 is allowed to travel laterally so as to heat the lower course of bricks. f

, It is to be noted that as'soon as the outer part of the arch. is brought to the desired temperature, the fire is forced to the limit in order to cause the heated zone, which extends only a slight way fromthe dog house toward the middle of the kiln, in a horizontal direction, to extend entirely across the l bottom of the kiln. This is necessary in order to keep the yburning under proper control. If the .fire be advanced slowly` thetendency will be to allow the heated vapors f and flames to rise up through the bricks -be-I 'Y fore the entire lower course becomes heated. If the incandescent zone be not made to extend completely'across the lower courses, the fire will gradually vcreate a Zdraft through the kiln of bricks adjacent to the outer wall, somewhat as indicated by the dotted lines 21 in Fig. 1. The effect of this would be to allow an escape for the products of combustion and it would be lpractically impossible -I to burn the centra-l coreof the kiln, inasmuch as the tendency of the heat would be to escape through the path defined by the dotted'linesu 21. This has been one of the chief difficulties .in previouslyknown proof esses for burning bricks.

A s previously stated, the purpose of forcing the lire is to cause the zone of incandescence to extend evenly across the bottom ofthe kiln substantially at right angles to the generalcourse of escape of the products of combustion, which is through the -kiln result is accomplished, which is very beneficial in the process of burning bricks. First,

the vapor, or water smoke, as it is termed by the attendants, is driven off from the bricks faster than the regular kiln draft can carry it away.` As a consequence, it forms what is known as a blanket of steam above the incandescent zone. Hence, due to the rapid firing, the draft immediately zalove the incandescent part is so greatly impeded as to be practically shut off and the escape for the products 'of combustiony is easier through the central part of the kiln, which is shown in the shaded central part in Fig. l. As the products of combustion escape through the central part of the stack, the incandescent zone will be advanced in that direction and, as a consequence, at the end of a certain period, which varies with the moisture content of the brick and with the steam pressure upon the burner, a complete blanket of. steam will be formed above the incandescent zone and the draft through the entire kiln will be impeded by this so-called blanket of steam. When this action occurs the entire lower course of `bricks is neces-` sarily at incandescent temperature, inasmuch as the incandescent state is what brings about the blanket of steam. As a consequence the kiln will settle, inasmuch as the central part, which would tend to support the same, has also become softened with heat, and a slight settle over the entire topv of the stack may be observed. At this stage l j of the burning the use of the burners forA -supplying fuel is discontinued'. It is to be 1 noted at this point that, due to obtaining an 'is not detrimental to burning incandescent zonel extending entirely across the bottom of the kiln, the settle of the kiln` and does not cause vbreakage of the bricks, as would be the case and as has been the case in burning bricks according to previously known processes. If the fire were allowed to burn slowly and take its course upward between the heavy dotted lines'21 as shown inFig.

. bricks defined by these lines are incandescent 1, a settle would eventually occur which would tend to break the bricks extending across these dotted lines 21, inasmuch as the and the bricks in the part toward thecenterl of the stack are still practically. green or unburned and are slowly'heated up by the re. It can also be seen that it will take a much longer time for the re'to reach the central core, or inverted-cone-shaped portion, if the fire is once allowed to escape, as'` between the dotted lines 2l.

Figi?) illustrates the stage of burning at bricks.

which the zone of incandescence extends across the bottom of the kiln. At this point, as above described, the use of fuel is discontinued and the induction pipes, which are described and claimed in my co-pending ap plication Serial No. 15,909, led March-20th, 1915, are then inserted in the arches and the burners which now form steam jets are connected thereto, to blow a blast of steam into these pipes 22, which have openings 2 3 at regular lntervals, to direct the steam and induced air blast upward into the kiln.

The burners 13 need not all be shut off at the same time as it is desirable under certain circumstances to continue iiring longer in some parts of the kiln than others, due to 'rise through the kiln. The green or unburned bricks are relatively cold and wet andtend very quickly to chill and condense the moisture which is entrained in the air and products of combustion, and, due to this condensing action, as well as due to `the fact that the pressure at this point is considerable owing to the' driving o of moisture from the bricks below, a very considerable impedance to the-flow of air or products of combustion .through the kiln is offered. The moisture which vcomprises this blanket of steam comes not only from the Water -which is driven off from the green bricks, but is present due to its formation in the process of burning the hydro-carbon fuel, and due, also, to the dehydration of certain of the chemical constituents of the bricks themselves. It can thus be seen that the air or products'l of combustion which pass upward from the incandescent zone are very heavily laden with moisture, and contact with the relatively Jcold green bricks tends tor condense the moisture, and, las is well known, a mist or` condensing vapor is ica lll@

lili@ very thick and cohesive in comparison with a gas-or superheated vapor.

When the fire is shut-off at the burners 13, the -kiln itself contains a certain number of heat units which are now`utilized in burning or bringing to the desired point of fusion the remainder ofthe kiln or stack of The result which is now to be described is not ascribed solely tothe amount of heat imparted to the' lower course of bricks, but it appears to be true that this preliminary heating is absolutely necessary in carrying out the process and in getting the kiln into a proper condition whereby the remainder of the bricks may be burned according to this process.

As soon as the induction pipes 22 are placed in position in the arches, the dog houses may be partially closed off to regulate the amount of air passing into the kiln and the steam is then turned onthrough the burners 13, great quantities of steam and a'ir being forced through these induction tubes up through the zone of incandescence into the main body of the kiln, I have found that the use of the induction tubes is not ab-A solutely essential as the air may be swept in j by the force. of the steam jet through the openings of the dog houses. y'Ihe induction tubesserve as means aiding in eiiiciently in jecting and distributing ,y the air and the steam. In such case it is not absolutely nece'ssary to shut oif the fire completely but the same may be merely reduced and the preponderence of steam and air made so great as'to carry out the process. The final result is that the zone of incan descence travels :5 upward in the general direction of the line of escape of the products of combustion until, at the end of a given time, which varies with the kind'of clay of which the bricks are composed, the amount of draft, the size 40 of the kiln, and so on, the zone of incandescence will have been driven up through the entire stack and will have reached the top thereof. At this point the blowing is discontinued and the kiln is allowed to cool, 5 after which the same is a finished product,

as the burning is completed.

The precise action involved in the ste of causing the heat to traverse the entire iln is somewhat obscure, butithe general prin- 0 ciple is that of the tireless cooker. A certain amount of heat has been put into the kiln at one part thereof and this heat is caused to act in turn upon the entire stack. The maintenance of the blanket of steam 5 ahead of the zone of incandescence appears to be essential in order to conserve and to prevent spreading or dissipation of this zone of incandescence over too great an area or v at too rapid a rate. The air which is ini duced in with the steam serves to support combustion of the carbonaceous matter in the bricks themselves, and' serves also as a medium for carrying 4the moisture, as it is well known that air acts as a sort of sponge to o5 take up moisture and carry the same along with it. A After the air and products of combustion have assed through the zone of-incandescence, t e moisture which has become entrained in these gases is again given up above the Zone of incandescence, due to the condensing action previously described, and the blanket of steam is maintained not only by driving off the water vapor from the bricks themselves, but by the steam which is carried in the air and by the water which is driven oli' in the process of dehydrating certain of the chemicals present in the bricksv themselves.

It has been found that the use of steam for producing the blast is not absolutely essential in certain cases, but it is undoubtedly true that this steam aids very of certain of the chemical components of the clay, it is obvious that this atmosphere, having one-third oxygen by volume, is better adapted than the atmospheric air which comprises essentially four parts of nitrogen to one part of oxygen by volume, and the molecular pressure of oxygen in an atmosphere of dissociated steam would be twicel as great as in an atmosphere of atmospheric air.

It is to be noted throughout that I maintain a pressure balance inside the kiln at all times in carrying out this process. The liring by the burners is under forced draft, at all times suiiicient to create enough pressure in the furnace-to expel any air except? that used for combustion. The pressure 1n the kiln is always slightly greater than the pressure outside, due to the expansion of the air caused by burning fuel, and due also to the pressure caused by the velocity head of the steam. While ring is carried on, it can be noted on the outside of the kiln that there is no leakage of air inward into the kiln through the outer wall 3. If any small holes exist in this wall 3 the escape of water smoke, or products of combustion may be noted at all times. The blowing by the steam nozzle and induction pipe is carried on at a velocity-sufficient to supply the pressure formerly caused by the expanding air which was previously supplied in firing by the burners, and is also suiiicient to force the incandescent zone and the blanket of steam through the kiln. As a result of this continuous pressurethere is very little dissipation of the heat originally put into the kiln, there is practically no loss of draft, and the control that the operator has over the continuation of the process is practically absolute. That is to say, the burning cannot get away from Athe operator if` he em` ploys reasonable care.

While I have described the carrying out of 'my process with considerable detail, in order to make clear to those skilled in the art the manner in which the same is to be practised, Ido not intend. that my Ainvention shall be limited to the precise steps or proportions Lacona@ 3 be apparent to those skilled in the art, to

line of travel vof the products of combus-v come within the vention.

- What f by Letters Patent of the United States is:

l. The process of burning bricks which consists in setting the saine in a kiln to have an internal furnace,l then heating lthe furspirit and scope of'. my innace with fuel under forced'draft suiicient to create enough pressure in the furnace to expel any air except that introduced for `combustion, and at a rate sufficient to evaporate the water in the bricks faster. than the kiln draft will carry the same od, thereby causing a damper of steam to form between the -heat zone and the exit of the products of combustion, the re being forced to cause the generation of a zone of incandescence substantially at right a'ngles to the general tion, said zone being brought to the temperature of fusion, then substantially discontinuing the firing by fuel and continuing the forced draft to ll the furnace and to maintain a pressure balance between the inside and the outside of the kiln,'thereby moving the zone of incandescence and the 1 blanket of steam ahead of it through the re- `mainder of the kiln.

2. The process of burning bricks ,which consists of setting the bricks into a lln,

firing said bricks under forced draft the rate of firing being such as to create a slight pressure above atmospherlc at the base of the kiln, and of such intensity as to create a zone of incandescence lying at substantially right angles to the general travel of the products ofy combustion through the kiln, and a body of steam above the zone of incandescence for preserving the heat in that zone, blowingv an excess of steam and air into said zone of incandescence to cause the same to move in the general direction of Y the line of movement of the products of combustion until said zone of incandescence has been caused to travel the entire height of the kiln, and shutting olf the fuel prior greater rate than the same is carried off by j the kiln draft, to bring to the temperature. of vitrification a stratum of said bricks adjacent to said heating chamber and extending substantially at right angles to the line of travel of theproducts of combustion,

claim as new and desire to secure' @fait then cutting 0H the fuel and continuing the forced draft with such pressure as will maintain within the kiln a greater pressure than the atmospheric pressure outside, thereby driving the heat from said heated stratum to the adjacentstrata of unburned bricks to drive off the moisture and bring them to the temperature of vitrification in progression.

. 4. The process of burning bricks which consists in .setting the same in a kiln for1ning internalvfurnaces, then burning fuel under forced draft in 'said furnaces, 4said forced draft being maintained with suffi i cient pressure to drive olf the moisture from the unburned bricks vat a greater rate than the kiln draft will carry the same 0E, to create a blanket of steam above the zone of the fire, the lire being continued until there is created a stratum of incandescent bricks adjacent said furnaces, then substantially discontinuing the fuel supply ,and continuing the forced draft to cause the zone of incandescence and the blanket of steam to travel to an adjacent stratum of unburned` brlcks andbringingthe same to the telnacross the kiln and heating the bricks in said zone to the temperature of fusion, then substantially discontinuing the firing and continuing the' forced draft to drive the blanketl of steam forward from adjacent strata and causing said heated zone to travel successively to said strata, to bring to the temperature of fusion the adjacent unburned bricks in said kiln.

6. The l process of burning bricks which consists in setting the bricks in a kiln forming internal furnaces, then heating the fur naces with fuel burned under a forced pressure draft, said fire being great enough to drive the water smoke and other vapors from the lower stratum of bricks adjacent thel furnaces at a greater rate than the kiln draft will carry them off, thereby forming ahead of the heated zone a blanket of steam, said firing being carried on at such a speed as to prevent the entry of air into the kiln other than that introduced. for supporting combustion, said firing being continued u ntil said lowerstratum is brought to the tem- -perature of fusion, then substantially discontinuing the ring and continuin the forced pressure draft at a speed su cient to maintaln .a pressure balance in said kiln and to move said blanket of steam forward from said incandescent zone, and causing said incandescent zone to travel to successive strata continuously until the desired temperature of vitrification shall have been attained by said adjacent strata.

7. The process of burning bricks which consists in setting said bricks into a kiln forming furnaces therein, then firing said furnace with liquid fuel by means of a steam jet to create a forced pressure draft, said forced pressure draft being suiiicient to cause a pressure inside of said kiln to exclude air therefrom other than that introduced to support combustion of the liquidl til a highly heated, substantially isothermal zone is attained in the stratum adjacent said furnace, the bricks adjacent said zone being still at the temperature at which they give off water smoke and other vapors, then substantially discontinuing firing and maintaining the forced pressure draft by discharging jets of steam in said furnace at a rate sufficient to maintain a pressure in said kiln slightly above atmospheric pressure, thereby causing said highly-heated v zone to travel from the lower stratum to adjacent higher strata.

In witness whereof, I hereunto subscribe my name this 12th day of March A. D. 1915.

' FRANK B. LAMBERT.

Witnesses:

LESLIE W. FRICKE, ERNEST W. ROPALU. 

